Circle
Calculate area, circumference, and diameter of a circle.
Circle Guide
A circle is one of the fundamental geometric shapes, defined as the set of all points in a plane at equal distance from the center.This distance is the radius (r), and the diameter (d) is twice the radius. A circle is a special case of an ellipse where all axes are equal.
The number Pi (π) is the ratio of a circle's circumference to its diameter.It's a mathematical constant with an approximate value of 3.14159 that never ends and never repeats. Pi is irrational, meaning it cannot be exactly expressed as a fraction of two integers. It's used in all calculations involving circles and circumferences.
The circumference of a circle is calculated using the formula 2πr or πd.The radius (r) is the distance from the center of the circle to any point on its circumference. The diameter (d) passes through the center and connects two opposite points on the circumference. Knowing one of these parameters, you can easily calculate the other values.
The area of a circle is calculated using the formula πr².This is the surface enclosed inside the circumference. For a circle with a radius of 10 units, the area will be π × 10² = 100π ≈ 314.16 square units. The area can also be expressed using the diameter: P = (πd²) / 4.
Practical applications.Circle formulas are widely used in engineering, architecture, physics, and many other fields of science. From designing car wheels, to calculating window areas, to determining satellite trajectories - wherever circular shapes appear.